Answer:
The Panama canal
Explanation:
Opened in 1914, the Panama canal allows maritime traffic to travel between the Pacific and Atlantic oceans very rapidly through a system of locks (2 on the Pacific side, one in the Atlantic side), and the boats pass through an artificial lake crossing the whole country of Panama.
It takes just a few hours to cross from one side to the other, while it would take weeks to go down to the tip of South America and back up.
In 2016, the canal opened new locks, that can receive larger boats.
The best answer is reduction in acid rain.
Acid rain is rainfall which has been rendered acidic by pollutants in the atmosphere. This kind of rain is typically harmful to forests and lakes.
The main cause of acid rain is human activities. The burning of fossil fuels such coal in electrical generating plants and crude oil products such as gasoline and diesel in car engine releases sulphur dioxide and nitrogen oxide into the atmosphere.
These compounds mix with water very high up in the atmosphere and form acid pollutants which fall on the ground as acid rain.
Use of clean energy will eliminate burning of fossil fuels and thus no acid rain will be produced.
Latitude determines the climate in any given location